The Age of Imperialism is a time period that occurred during the 1800's and the first half of the 1900's. During this time, powerful nations controlled the political, economic, and social policies of other nations.

The United States actually arrived late to the Imperialist party. Due to factors like the Civil War, Reconstruction, and Westward Expansion, the US was not a major imperialist power until the late 1800's with the onset of the Spanish-American War.

The desire for new markets, raw materials, social influence, and the desire to flex its military muscle led the US into the war with Spain. The outcome was a subservient Cuba, war in the Philippines, and the additions of Guam and Puerto Rico as territories.

Besides these acquisitions, the war served as a "coming-out party" for the US. It was now a major player on the world stage. The bastion of democracy, limiting the freedoms of the people that lived in the territories they acquired.